Assessment of Soil Quality of Tidal Marshes in Shanghai City

We take three types of tidal marshes in Shanghai City as the study object:tidal marshes in mainland,tidal marshes in the rim of islands,and shoal in Yangtze estuary.On the basis of assessing nutrient quality and environmental quality,respectively,we use soil quality index(SQI)to assess the soil quality of tidal flats,meanwhile formulate the quality grading standards,and analyze the current situation and characteristics of it.The results show that except the north of Hangzhou Bay,Nanhui and Jiuduansha with low soil nutrient quality,there are not obvious differences in soil nutrient quality between other regions;the heavy metal pollution of tidal marshes in mainland is more serious than that of tidal marshes in the rim of islands;in terms of the comprehensive soil quality index,the regions are sequenced as follows:Jiuduansha wetland>Chongming Dongtan wetland>Nanhui tidal flat>tidal flat on the periphery of Chongming Island>tidal flat on the periphery of Hengsha Island>Pudong tidal flat>Baoshan tidal flat>tidal flat on the periphery of Changxing Island>tidal flat in the north of Hangzhou Bay.Among them,Jiuduansha wetland and Chongming Dongtan wetland have the best soil quality,belonging to class III,followed by Nanhui tidal flat,tidal flat on the periphery of Chongming Island and tidal flat on the periphery of Hengsha Island,belonging to class IV;tidal flat on the periphery of Changxing Island,Pudong tidal flat,Baoshan tidal flat and tidal flat in the north of Hangzhou Bay belong to class V.

Response of gaseous carbon emissions to low-level salinity increase in tidal marsh ecosystem of the Min River estuary,southeastern China

Although estuarine tidal marshes are important contributors to the emission of greenhouse gases into the atmosphere, the relationship between carbon dioxide（CO2）, methane（CH4）emission, and environmental factors, with respect to estuarine marshes, has not been clarified thoroughly. This study investigated the crucial factors controlling the emission of CO2 and CH4from a freshwater marsh and a brackish marsh located in a subtropical estuary in southeastern China, as well as their magnitude. The duration of the study period was November 2013 to October 2014. Relevant to both the field and incubation experiments, the CO2 and CH4emissions from the two marshes showed pronounced seasonal variations. The CO2 and CH4emissions from both marshes demonstrated significant positive correlations with the air/soil temperature（p 〈 0.01）, but negative correlations with the soil electrical conductivity and the pore water/tide water Cl-and SO42- （p 〈 0.01）. The results indicate no significant difference in the CO2 emissions between the freshwater and brackish marshes in the subtropical estuary, whereas there was a difference in the CH4 emissions between the two sites（p 〈 0.01）. Although future sea-level rise and saltwater intrusion could reduce the CH4 emissions from the estuarine freshwater marshes, these factors had little effect on the CO2 emissions with respect to an increase in salinity of less than 5‰. The findings of this study could have important implications for estimating the global warming contributions of estuarine marshes along differing salinity gradients.

Lessons from the past:isotopes of an endangered rail as indicators of underlying change to tidal marsh habitats

Introduction:Tidal marsh systems along the Pacific coast of the United States have experienced substantial stress and loss of area and ecosystem function,which we examined by using the endangered California Ridgway’s Rail,Rallus obsoletus obsoletus(‘rail’)as an indicator of its tidal marsh habitat in the San Francisco Estuary.We organized a collection of historical(1885-1940)and modern(2005-2014)rail feathers and analyzed the feather isotope means for delta carbon(δ^(13)C),sulfur(δ^(34)S),and nitrogen(δ^(15)N)by region and time period.Outcomes:Feather isotopes represented the primary foraging habitat during historical then modern time periods.Neither individual nor regional rail feather isotopes suggested freshwater or terrestrial foraging by the rail.Three regions with both historic and modern feather isotopes revealed non-uniform spatial shifts in isotope levels consistent with a marine based food web and significantδ^(15)N enrichment.Discussion:Our results supported the rail’s status as a generalist forager and obligate tidal marsh species throughout the historic record.The variable isoscape trends generated from feather isotope means illustrated a modern loss of the isotopic homogeneity between regions of historical tidal marsh,which correlated with spatially-explicit habitat alterations such as increasing biological invasions and sewage effluent over time.Conclusion:These findings have reinforced the importance of tidal marsh conservation in the face of ongoing underlying changes to these important ecosystems.

Processes of small-scale tidal flat accretion and salt marsh changes on the plain coast of Jiangsu Province,China

Large-scaled reclamation modifies the coastal environment dramatically while accelerating the disappearance of salt marshes,which causes the degradation of the coastal ecosystem and the biodiversity function.In this study,we explored the changes of tidal flat and salt marsh coverage in a small-scale tidal flat with an area of ~160 000 m^2 in the plain coast of Jiangsu Province,China.Human activities（e.g.,the construction of dikes） are a crucial contributor that benefits for the tidal flat accretions and the following changes of salt marsh coverage.Located in the front of the man-made ＂concave coastline＂,the study area is suitable for sediment accretion after the dike construction in the end of 2006.On the basis of the annual tidal surface elevation survey from 2007 to 2012,the sedimentation rates in the human influenced tidal flat varied from a few centimeters per year to 23 cm/a.The study area experienced a rapid accretion in the tidal flat and the expansion of the salt marsh,with the formation of a longshore bar,and a subsequent decline of the salt marsh.Breaking waves during the flooding tide brought much sediment from the adjacent tidal flat to the study area,which caused burial and degeneration of the salt marsh.The vertical grain size changes within a 66 cm long core in the study area also demonstrated the above changes in the tidal environment.This study indicates that the responses of small-scale tidal flat changes to reclamation are significant,and the rational reclamation would benefit for the new salt marsh formation in front of the dikes.Further research about the evolution of small scale tidal flat as well as the spatial planning of the polder dike should be strengthened for the purpose to maintain a healthier coastal environment.

Composition of fish communities in an intertidal salt marsh creek in the Changjiang River estuary,China

Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year.A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected.Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%),Collichthys lucidus (18.6%),Periophthalmus magnuspinnatus (18.2%),Liza haematocheilus (17.9%),and secondarily by Mugilogobius abei (8.5%),L.carinatus (7.2%),Odontamblyopus lacepedii (4.3%),and Acanthogobius ommaturus (3.9%);another 18 species were present only occasionally.Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek.In spring,the communities were dominated by B.pectinirostris,P.magnuspinnatus,C.lucidus and M.abei;in summer,autumn,and winter by L.haematocheilus,L.carinatus,A.ommaturus and O.lacepedii.Some species showed strong habitat selection;L.carinatus and P.magnuspinnatus were distributed mainly in the upper and middle creek,while B.pectinirostris,M.abei and O.lacepedii inhabited the middle and lower creek.The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.

Discovery and features of vertical zonations of tidal salt-marsh foraminifera in Jianchuan, North Jiangsu Province, China

Through densified surface sampling of foraminifera and accurate elevation measurement a-long three transect lines in open-coast tidal salt-marsh of Jianchuan, particular salt-marsh foraminifera assemblages were found. The salt-marsh foraminifera assemblages are distributed in well-defined vertical zonations with respect to elevation and closely parallel marsh floral zonations. At the top of the vertical zonation all foraminifera disappear abruptly which are accurately located at the highest high water datum. This distribution pattern can be used to relocate former sea levels accurately (to an accuracy of within ±5 cm). A modern regional criterion of foraminifera for relocating the former sea levels in high resolution in our country is provided, and deficiencies of studying the vertical zonation only in sheltered coast salt-marsh abroad are filled up.

COASTAL SALT MARSHES AND MANGROVE SWAMPS IN CHINA

Based on plant specimen data,sediment samples,photos,and sketches from 45 coastal cross-sections,and materials from two recent countrywide comprehensive investigations on Chinese coasts and is-lands,this paper deals with China’s vegetative tidal-flats:salt marshes and mangrove swamps.Thereare now 141700 acres of salt marshes and 51000 acres of mangrove swamps which together cover about30% of the mud-coast area of the country and distribute between 18°N(Southem Hainan Island)and41°N(Liaodong Bay).Over the past 45 years.about 1750000 acres of salt marshes and 49400 acres ofmangrove swamps have been reclaimed.The2.0×10~9 tons of fine sediments input by rivers into the Chinese seas form extensive tidal flats,the soil basis of coastal helophytes.Different climates result inthe diversity of vegetation.The 3～8m tidal range favors intertidal zone development.Of over 20plant species in the salt marshes,native Suaeda salsa,Phragmites australis,Aeluropus littoralis,Zoysiamaerostachys,Imperata cylindrica and

Impact of Sediment Supply on Spartina Salt Marshes

During the past century,natural and human modifications of environmental systems have greatly accelerated coastal salt marsh deterioration and shoreline retreat in many regions worldwide. Field investigation,profile analysis,geographical information analysis,and remote sensing were employed in combination to study the effect of sediment on Spartina alterniflora salt marshes of the coast in Jiangsu Province,East China. The results indicated that the propagation of Spartina alterniflora salt marshes was closely related to regional sediment conditions,especially the supply of fine-grained materials. Additionally,because of the dense and high grass in Spartina alterniflora salt marshes,wave energy and tidal currents were baffled and weaker than those of the adjacent,unvegetated mud flats. Fine sediment was hardly resuspended under the low energy conditions in the Spartina alterniflora salt marshes.

潮滩前缘盐沼植被簇团与潮沟系统演变相互作用研究

潮滩前缘盐沼植被簇团可以通过改变水动力及泥沙运动等过程影响潮沟系统的地形地貌,而潮沟系统的地形特征也会影响盐沼簇团的生长、扩张与侵蚀,但对盐沼簇团与潮沟系统地貌演变的相互作用机制尚缺乏认识。针对这一问题,本文构建了考虑盐沼植被动态演变的潮滩生物动力地貌耦合模型,模拟了盐沼植被簇团生长扩张与潮沟系统地貌演变过程,分析了不同初始数量的盐沼植被簇团与潮沟系统的空间格局及形态参数间的双向反馈。结果表明,潮沟先迅速向海陆两侧延伸,后发育出大量分汊;盐沼簇团向周边扩张后未被潮沟切割区域逐渐连成片。少量盐沼簇团能够增加潮沟密度,促进边缘冲刷式潮沟系统的发育。潮沟的走向受盐沼簇团分布位置及数量的影响,多个盐沼植被簇团间的水流集中比单个簇团的边缘水流冲刷更易形成潮沟。在盐沼植被簇团与潮沟系统共同发育初期,潮沟系统发育受盐沼植被簇团的促进作用较大,后期潮沟内比簇团边缘更易形成水流汇聚,盐沼簇团的影响逐渐由促进作用转为稳定作用。此外,潮沟的存在限制了盐沼植被的横向扩散,切割了盐沼植被簇团,影响盐沼植被的空间分布格局。本研究揭示了盐沼植被簇团与潮沟系统地貌耦合演化机制,可为盐沼潮滩生态系统保护修复提供科学依据。

南通典型断面盐沼植被对潮间带潮流泥沙输运的影响研究

在人类活动和自然灾害的双重作用下,我国部分海岸带生态系统已表现出明显的脆弱性。盐沼植被具有消浪弱流和保滩促淤等功效,盐沼植被引种也成为了海岸生态修复和恢复中关键举措之一,研究盐沼植被引种具有重要的实际意义。依据研究区域的实测地形及潮流泥沙等数据资料,对盐沼植被引种前后的潮流泥沙进行了数学建模,研究了植被引种对潮流泥沙的影响。研究结果表明,盐沼植被引种后,流速、含沙量、悬移质瞬时输运量、推移质瞬时输运量等量值上均有不同程度的减小,减小幅度大都超过50%;在盐沼前缘向岸一定距离内,盐沼植被具有明显的促淤效果;盐沼植被引种会改变潮滩局部地貌,植被密度、植被分布区域增大均会引起深度较大、宽深比较小的潮沟发育,而植被分布区域增大作用下的潮沟发育更为显著。

闽江河口潮滩季节性冲淤变化格局及其控制机制

潮滩是潮汐作用下形成的细颗粒沉积物堆积体,在世界范围内分布广泛,在碳汇和海岸防护中发挥着十分重要的作用。随着河流输沙的减少,河口潮滩冲淤格局发生了变化,直接影响了潮滩功能发挥,亟需开展河口潮滩短周期的冲淤变化过程研究,为评估潮滩功能提供科学依据。根据在福建闽江口琅岐岛潮滩开展的不同季节沉积动力要素(水深、流速、波浪、悬沙浓度)和现场冲淤观测及表层沉积物的粒度分析结果,琅岐岛潮滩表层沉积物在夏季主要以粉砂和黏土组成的细颗粒沉积物为主,冬季则主要以砂和粉砂组成的粗颗粒沉积物为主;潮间带上部的互花米草盐沼总体以持续淤积为主,潮间带中部和下部表现出周期性的冲淤特征,总体以夏季淤积、冬季侵蚀为总特征,并且潮间带中部的冲淤变化幅度较潮间带下部大;冬季潮流流速、波浪作用及悬沙浓度均大于夏季,冬季潮周期内近底部悬沙以净向海输运为主,而夏季则以净向岸输运为主。综上所述,闽江口潮滩冲淤变化主要受动力过程控制,冬季波浪作用导致表层沉积物发生再悬浮,并被较强的潮流净向海输运,导致滩面发生侵蚀;夏季,波浪作用较弱,水体中的悬沙易发生沉降,较弱的潮流将泥沙净向岸输运,导致潮间带发生淤积。

闽江河口淡水、半咸水沼泽土壤碳氮磷分布及计量学特征

以闽江河口区淡水、半咸水短叶茳芏沼泽湿地为研究对象,于2013年11月~2014年8月分季节采集表层土壤样品,研究土壤有机碳（SOC）、总氮（TN）、总磷（TP）含量时空变异格局及其计量学特征,并同步观测相关环境因子.结果表明,淡水、半咸水沼泽土壤SOC、TN、TP含量范围分别为（18.24~28.36,1.44~2.24,0.45~1.01）（14.96~26.19,1.55~2.45,0.67~1.18）g/kg.淡水沼泽土壤各元素含量均具有明显的垂直变化规律;而半咸水沼泽除TN含量垂直变异明显外,其他各指标则表现为波动变化的特征.淡水、半咸水沼泽土壤C/N、C/P、N/P均值分别为12.41±1.22,29.77±6.76,2.40±0.47以及10.89±1.09,24.92±3.80,2.29±0.25.方差分析显示,各指标含量在两个沼泽均存在显著空间差异.两个沼泽土壤SOC、TP、C/N、C/P均与土壤p H和EC呈显著相关关系,而与含水率和容重相关性不显著;土壤C/N均与粉砂粒和砂粒呈极显著相关关系;土壤SOC、TN、TP含量对C/N、C/P、N/P影响显著.淡水、半咸水沼泽土壤营养元素含量分布特征是水动力学作用、外源物质输入、植物生产力和人类活动等多因子综合作用的结果.

长江口潮沼植物对动力沉积过程的影响

为探讨潮沼植物对动力沉积过程的影响 ,在长江口南汇东滩沼泽和邻近的光滩上进行了近底层流速、波浪、悬沙浓度、沉积物粒径和滩面淤积速率等对比实验 ,并在九段沙潮沼中做了两种先锋植物黏附悬沙的实验 .结果表明 ,沼泽和同高程的邻近光滩近底层平均流速的比值为 0 .1 6～ 0 .84;两种环境平均波周期、平均波高和平均悬沙浓度的比值分别为 1 .4,0 .43,和 0 .71 .波浪传入沼泽后 ,一方面波高大大降低 ,另一方面变得规则有序 .海三棱草和草两种先锋植物群落黏附的悬沙分别达到 2 98和40 g/m2 .由于水动力降低和植物的捕沙功能 ,细颗粒泥沙易于在沼泽中沉积下来 ,导致沼泽环境沉积物明显较相邻光滩细 ;沼泽中沉积速率加快 ,侵蚀受到抑制 .

黄河口新生湿地碱蓬生物量及氮累积与分配对外源氮输入的响应

2014年4—11月,选择黄河入海口北部滨岸高潮滩的碱蓬湿地为研究对象,基于野外原位氮输入模拟试验,研究了不同氮输入梯度下(N0,无氮输入;N1,低氮输入;N2,中氮输入;N3,高氮输入)碱蓬不同器官生物量以及氮累积与分配特征的差异。结果表明,尽管不同氮输入处理并未改变碱蓬地上生物量的季节变化模式,但在不同程度上均促进了地上生物量的增长(平均增幅为19.71%—62.29%)且整体表现为N3>N2>N1>N0;不同氮输入处理亦延长了碱蓬的生长高峰期,N1、N2和N3处理下地上生物量达到最大值的时间相对于N0处理推迟20 d左右。与地上生物量不同,不同氮输入处理改变了地下生物量的季节变化模式,特别是N2和N3处理均对生长初期的地下生物量产生了明显促进作用,且其初期地下生物量达到较高值的时间相对于N1和N0处理提前20—50d。不同氮输入处理下的枯落物量在产生初期和中期均增幅不大,末期则骤然增加且整体表现为N3>N2>N1>N0。不同氮输入处理下碱蓬各器官的全氮(TN)含量总体上均表现为叶>茎>根,叶是氮的主要累积器官。尽管不同氮输入处理并未改变碱蓬不同器官的氮累积与分配格局以及地上与地下之间的养分供给关系,但其为适应不同养分条件而调整自身养分供给与分配的特性在N2处理下表现的尤为明显。研究发现,N2处理下碱蓬种子的发育时间相对于N0、N1和N3处理可能会提前约1个月,原因可能与N2氮输入水平可显著影响碱蓬体内的碳分配比以及碱蓬对适量氮养分输入环境的特殊适应对策有关。随着黄河口新生湿地氮养分供给的不断增加,当未来碱蓬湿地氮养分状况达到较高水平(特别是中等水平)时,其生物量、生长节律(特别是种子发育时间)以及不同器官氮累积与分配状况可能将发生明显改变。

黄河三角洲潮间带不同类型湿地景观格局变化与趋势预测

以1979—2013年7期卫星遥感影像(Landsat TM)为数据源,结合野外实地调查,通过建立黄河三角洲潮间带湿地数据库,探讨不同类型湿地的景观格局以及自然与人为因素对景观格局变化的影响,并基于Markov模型对未来20年三角洲潮间带不同类型湿地的景观格局进行了趋势预测。结果表明,三角洲的潮间带湿地面积在1979—2013年间整体呈先降低后增加变化。其中,1979—2010年的湿地面积持续减少,由1050.28 km^2减少为575.39 km^2,减少率为45.22%;2010—2013年的湿地面积略有增加,由575.39 km^2增加为596.17 km^2,增长率为0.36%。1979—2013年,潮间带主要湿地景观类型随距海远近均呈明显带状分布,但芦苇湿地面积呈明显降低趋势(减少273.53 km^2,减少率为79.68%),盐田养殖池面积呈显著增加趋势(增长12.04km^2,增长率为1584.21%),而光滩、碱蓬湿地、碱蓬-柽柳湿地和柽柳-芦苇湿地等其它类型湿地面积整体均呈波动减少趋势。未来20年,潮间带湿地面积整体将呈降低趋势,其值将由2010年的575.39 km^2减少为2030年的546.98 km^2,减少率为6.60%。芦苇湿地面积将继续减少(减少30.16 km^2,减少率为24.12%),盐田养殖池面积将持续增长(增加3.71 km^2,增长率为38.61%),而光滩、碱蓬湿地、碱蓬-柽柳湿地和柽柳-芦苇湿地等其它类型湿地面积均将呈小幅波动变化。研究发现,尽管自然与人为驱动力的双重作用决定了1979—2013年间潮间带的湿地景观格局及其动态变化,但黄河年输沙量(x_1)、区域GDP(x_2)和水产品产量(x_3)对潮间带湿地面积变化(y)的影响更为重要(y=733.192+35.317 x_1-0.005 x_2-4.085 x_3,P=0.0001<0.05),其对过去30多年间潮间带湿地面积变化的解释贡献高达76.7%。随着黄河三角洲高效生态经济区国家战略的实施,为实现潮间带区域的可持续发展,潮间带湿地的保护与生态保育应给予特别重视。

黄河口潮间盐沼湿地生长季净生态系统CO_2交换特征及其影响因素

潮间盐沼湿地生物地球化学过程独特,生态系统CO2交换存在着极大的复杂性和不确定性。利用2012年黄河口潮间盐沼湿地生态系统生长季(4—10月)连续的涡度相关观测数据,分析了潮间盐沼湿地的净生态系统CO2交换(NEE)、总初级生产力(GPP)和生态系统呼吸(Reco)的变化特征及其影响因素。结果表明:生长季,生态系统NEE具有明显的日变化和季节变化。日尺度上,表现为白天CO2净吸收,夜间CO2净释放,NEE日平均值为-0.38 g CO2m-2d-1;月尺度上,平均气温最高的7月生态系统释放CO2最多(15.16 g C/m2),6月生态系统吸收CO2最多(25.07 g C/m2)。潮间盐沼湿地生态系统的CO2交换受到光合有效辐射(PAR)、土壤温度(Ts)、土壤含水量(SWC)和潮汐淹水的共同影响。白天NEE主要受控于PAR,且生态系统表观初始光能利用率(α)和最大光合速率(NEEsat)分别在6月和5月达到最大值,分别为(0.0086±0.0019)μmol CO2μmol-1光子和(4.79±1.52)μmol CO2m-2s-1。夜间NEE随Ts呈指数增加趋势,生态系统呼吸的温度敏感性(Q10)为1.33,且SWC越高,Q10值越大。研究典型晴天(6月19日—6月25日)表明,潮汐淹水增强了生态系统白天对CO2的吸收,同时也增强了夜间CO2释放,研究时段内,潮汐淹水使生态系统净CO2吸收增加了0.76 g CO2m-2d-1。整个生长季,黄河口潮间盐沼湿地生态系统表现为CO2的汇,NEE为-22.28 g C/m2(其中,吸收118.34 g C/m2,释放96.28 g C/m2)。研究结果利于对潮间盐沼湿地源汇功能和影响机制的进一步认识与研究。

某石油污染滩涂沉积物中总石油烃和多环芳烃组成分布特征及源解析

对石油污染滩涂区域不同高程表层沉积物和部分垂直剖面沉积物进行采样分析,分别采用紫外分光光度法和气相色谱质谱联用法测定了沉积物中的TPH（总石油烃）和16种优控PAHs（多环芳烃）,分析其组成分布特征,并进行了源解析。结果表明：中低潮滩表层沉积物中TPH质量比在15.20~63.27 mg/kg,与对照点质量比水平相当,远低于《海洋沉积物质量标准》（1 000 mg/kg）,PAHs均未检出;高潮滩表层沉积物中TPH质量比在1 070.00~46 327.20 mg/kg,显著高于对照点和相应中低潮滩沉积物中污染物质量比,部分点位严重超出《海洋沉积物质量标准》,PAHs质量比在0.60~30.90 mg/kg,多数点位属于重度污染;3号点和7号点高潮滩垂直剖面样品中TPH和PAHs质量比呈现随深度增加而降低的趋势,9号点则相反;高潮滩沉积物中TPH和PAHs质量比之间呈显著正相关关系（Pearson相关系数r为0.985,p〈0.01）,具有同源性;各点位TPH均以C17~C36质量分数最高,其占比为80.15%~94.40%,PAHs组成均以2~3环为主,占比为58.14%~87.70%,低环PAHs以萘、芴和菲为主要污染物。TPH和PAHs组分特征表明,研究区域的滩涂沉积物受到了重油污染影响。

黄河口潮滩湿地土壤CH4氧化潜力及其对有机物输入的响应

2010年11月,采集了黄河口北部滨岸高潮滩、中潮滩、低潮滩和光滩表层土壤样品,基于短期培养实验,研究了不同潮滩土壤CH4氧化潜力及其对有机物输入的响应.结果表明,尽管4种湿地土壤的CH4氧化潜力存在一定差异（P＞0.05）,但整体变化规律相似.12～60 h,CH4氧化潜力均呈先增加后降低变化;60～132 h,CH4氧化潜力均呈迅速增加趋势.4种湿地土壤CH4氧化潜力整体表现为光滩（2.37 μg/g·d）＞低潮滩（2.29 μg/g·d）＞中潮滩（1.70 μg/g·d）＞高潮滩（1.47 μg/g· d）.甲醇输入整体抑制了湿地土壤的CH4氧化潜力,抑制程度表现为光滩＞中潮滩＞低潮滩＞高潮滩.4种湿地土壤的CH4氧化潜力分别为1.27,0.49,0.67和0.38 μg/（g·d）,较对照组降低13.56％,70.98％,70.65％和83.83％;酵母膏输入对高潮滩、中潮滩和光滩土壤的CH4氧化潜力表现为促进作用,促进程度表现为中潮滩＞高潮滩＞光滩.3种湿地土壤的CH4氧化潜力分别为2.89,2.41和2.96μg/（g·d）,较对照组增加69.38％,64.01％和24.76％.与之相比,酵母膏对低潮滩土壤的CH4氧化潜力表现为弱抑制作用,其氧化潜力为2.14 μg/（g·d）,较对照组降低6.67％.可见,不同有机物对潮滩湿地土壤CH4氧化潜力的影响差异较大,在当前外源有机物为黄河入海主要污染物情况下,潮滩湿地CH4的源/汇功能将会发生明显变化,这就使得在估算黄河口潮滩CH4排放清单时应特别关注不同有机物输入对CH4释放的影响.

黄河口滨岸潮滩湿地土壤碳、氮的空间分异特征

2009年5月,运用地统计学方法研究了黄河口滨岸潮滩湿地土壤碳、氮的空间分布格局。结果表明,潮滩湿地土壤的TC、TN和C/N含量具有明显的水平变异性,自表层向下均呈显著降低趋势,总体表现为TN>C/N>TC。潮滩湿地土壤不同土层TN和C/N含量的水平分布空间结构明显,分别符合不同的变异函数理论模型,且具有强烈/中等程度的空间相关性,其空间变异性均以向低潮滩延伸且受潮汐涨落影响较大的方向为最大,自然结构因素在引起TN和C/N空间异质性中的贡献占优,随机因素的影响相对较小。潮滩湿地土壤不同土层TN和C/N具有明显的空间分布格局,表层土壤的TN含量向低潮滩延伸方向形成明显斑块低值区,边缘则形成斑块高值区,而不同土层的C/N以及亚表层的TN则与之相反。研究发现,微地貌特征和潮汐微域物理扰动强度是导致空间异质性的重要随机因素,而水盐条件、土壤类型和潮汐物理扰动是重要结构因素。湿地有机质来源以陆源为主,且越靠近海的方向,潮滩湿地土壤中的有机质受陆源的影响越大。